Chemical analysis and the identification of biological materials have been carried out in the areas of analytical biology, chemistry, and physics. Typically, analytical methods used in these disciplines have required the use of cumbersome laboratory instrumentation in a centralized laboratory and long sampling and analysis times. However, increasing awareness and concern regarding factors that influence health, safety, appliance performance, and the environment have created a demand for user-friendly technologies capable of detecting, identifying, and monitoring chemical, biological, and environmental conditions in real-time. Given these trends, it is safe to predict that intelligent, portable, wireless, web-enabled, self-diagnostic appliances exploiting a broad range of chemical and biosensor technology will be in demand in the near future.
A number of conventional methods have been developed for detection of chemical or biological agents. For example, the immobilization of indicator biomolecules onto conductive polymer substrates as well as the develoμment of chemical and biological sensor devices based on electroconductive polymers is an area that has attracted considerable recent attention. However, these conventional chemical and/or biosensors are designed to operate in aqueous solution environments, not in the air or in the solid state.
In recent years, chemical or biological sensors based on semi-conducting nanowires, such as silicon and germanium, have become more important, as such nano-scale sensors can offer high sensitivity, low cost, high density arrays, and low power consumption, which characteristics are difficult to achieve with conventional sensors. As such, research in this area of chemical or biological sensing is ongoing.